1. Field of the Invention
This invention relates to articles having improved penetration resistance. More particularly, this invention relates to such articles which are fiber based and which are especially suitable for fabrication into penetration resistant articles such as body armor, as for example, bulletproof vests.
2. Prior Art
Ballistic articles such as bulletproof vests, helmets, structural members of helicopters and other military equipment, vehicle panels, briefcases, raincoats and umbrellas containing high strength fibers are known. Fibers conventionally used include aramid fibers such as poly (phenylenediamine terephthalamide), graphite fibers, nylon fibers, ceramic fibers, glass fibers and the like. For many applications, such as vests or parts of vests, the fibers are used in a woven or knitted fabric. For many of the applications, the fibers are encapsulated or embedded in a matrix material.
U.S. Pat. Nos. 3,971,072 and 3,988,780 relate to light weight armor and method of fabrication of same. Reinforced body armor and the like is fabricated by securing a thin ballistic metal outer shell to a plurality of layers of flexible material having qualities resistant to ballistic penetration. The layers of material are sewn together along paths spaced within a selected predetermined range, so as to restrict movement of the fabric layers in lateral and longitudinal directions and to compact the layers in an elastic mass thereby to provide improved resistance to penetration of the material by a ballistic missile and to reduce back target distortion.
U.S. Pat. No. 4,183,097 relates to a contoured, all-fabric, lightweight, body armor garment for the protection of the torso of a woman against small arms missiles and spall which comprises a contoured front protective armor panel composed of a plurality of superposed layers of ballistically protective plies of fabric made of aramid polymer yarns, the front protective armor panel being contoured by providing overlapping seams joining two side sections to a central section of the panel so as to cause the front protective armor panel to be contoured to the curvature of the bust of a female wearer of the body armor garment to impart good ballistic protection and comfort to the wearer.
U.S. Pat. No. 3,855,632 relates to an undershirt type garment made of soft, absorbent, cotton-like material, stitched thereto and covering the chest and abdomen areas and the back area of the wearer's torso. Inserted between each of the panels and the portions of the shirt which they cover is a pad formed of a number of sheets of closely woven, heavy gage nylon thread. The sheets are stitched together and to the shirt generally along their outer edges so that the major portions of the sheets are generally free of positive securement to each other and thus may flex and move to some extent relative to each other. Thus, the garment, in the padded areas, is substantially bullet-proof and yet is lightweight, flexible, non-bulky and perspiration absorbent.
U.S. Pat. No. 4,522,871 relates to an improved ballistic material comprising a multiplicity of plies of ballistic cloth woven with an aramid, e.g., Kevlar.RTM., thread, one or more of which plies are treated with resorcinol formaldehyde latex to coat the aramid threads and fill the interstices between the threads of a treated ply.
U.S. Pat. No. 4,510,200 relates to material useful in bulletproof clothing formed from a number of laminates arranged one on top of another. The laminates are preferably formed of a substrate coated with a crushed thermosettable foam that, in turn, covered with a surface film, which may be an acrylic polymer. The films should form the outermost layers of the composite material which together with the foam layer, prevent degradation of the substrate, which is typically formed of fabric woven from Kevlar.
U.S. Pat. No. 4,331,091 describes three-dimensional thick fabrics made from a laminate of fabric plies held together by yarns looped through holes in the structure. U.S. Pat. No. 4,584,228 layers of textile fabric or foil superimposed on a shock absorber, in which the shock absorber is a three dimensional fabric with waffle-like surface.
U.S. Pat. Nos. 4,623,574; 4,748,064; 4,916,000; 4,403,012; 4,457,985; 4,650,710; 4,681,792; 4,737,401; 4,543,286; 4,563,392; and 4,501,856 describe ballistic resistant articles which comprise a fibrous network such as a fabric or 0.degree./90.degree. uniaxial pregreg in a matrix.